This section is from the book "Wild Flowers East Of The Rockies", by Chester A. Reed. Also available from Amazon: Wild Flowers East Of The Rockies.
The Bur Reeds are marsh inhabiting plants, some growing along the muddy shores of ponds or streams, while other species are strictly aquatic, growing in the water with floating leaves. Like the Cat-tails they are not in the least dependent upon insects for fertilization. The two kinds of flowers, staminate and pistillate are always in separate spherical clusters, usually alternately arranged along the stem. While the upper flowers are developing, the middle ones are in full bloom and the lower ones have been transformed into spherical prickly fruit. Several varieties of Bur Reed are recognized, the ones here mentioned being the most common and the most characteristic.
A. Great Bur-reed.
B. Branching Bur-reed.
Great Bur-Reed (Sparganium Eurycarpum)is stout and erect, two to three feet in height. The mature heads, or fruit, are about one inch across; composed of wedge-shaped nutlets arranged in the form of a sphere, giving the outside a corrugated appearance similiar to the surface of a pineapple. The basal leaves are similar to those of the Cat-tail and clasp the stems at their bases. These plants are found in the whole of the U. S. and southern Canada, flowering from June to August.
Small Bur Reed (S. Simplex)is smaller in every respect; leaves shorter and narrower and the greenish fruit head less than 3-4 in. in diameter; the nutlets are very sharply pointed. This species is found in northern U. S. and southern Canada.
Branching Bur Reed (S. Androcladum)throws off several weak flower-bearing branches from the angles of the upper leaves.
Least Bur Reed (S. Minimum)is slender and ten to eighteen inches high; leaves grass-like, floating on the water; northern U. S. and Canada.